Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator, in thousands
Net income (loss) used for calculation of basic EPS	$ 2,005	$ 3,202	$ 2,923	$ (12,342)
Interest expense on convertible debt	331
Change in fair value of derivative liabilities	(195)
Loss on extinguishment of outstanding debt	241
Loss on extinguishment of outstanding debt, as if converted	(553)
Total adjustments	(176)
Net income (loss) used for calculation of diluted EPS	$ 1,829	$ 3,202	$ 2,923	$ (12,342)
Denominator
Weighted average shares outstanding, basic	47,911,932	42,056,285	46,246,866	41,595,232
Effect of dilutive potential common shares
Shares underlying Convertible Senior Secured Notes	2,417,586
Shares issuable to settle interest make-whole derivatives	246,105
Stock options, stock appreciation rights, and non-vested stock options	1,697,926	315,852	1,441,126
Total potential dilutive common shares	4,361,617	315,852	1,441,126
Weighted average shares outstanding, diluted	52,273,549	42,372,137	47,687,992	41,595,232
Net income (loss) per share, basic	$ 0.04	$ 0.08	$ 0.06	$ (0.30)
Net income (loss) per share, diluted	$ 0.03	$ 0.08	$ 0.06	$ (0.30)
7.50% Convertible Senior Secured Notes due 2019
Loss Per Share
Common stock equivalents excluded in the calculation of diluted loss per share		7,548,143	2,791,624	7,733,266
Warrant to purchase common stock
Loss Per Share
Common stock equivalents excluded in the calculation of diluted loss per share	28,613	20,571	25,950	20,928
Stock Options, Stock Appreciation Rights and Non-Vested Stock Options
Loss Per Share
Common stock equivalents excluded in the calculation of diluted loss per share				259,478